In rotator cuff repair and other surgical procedures, tendons or tissues that are separated from bone can be attached and secured to the bone with one or more tissue anchors. Tissue anchors can include a bone anchor portion that attaches to a bone, and one or more sutures that connect with the tissue being secured. The bone anchor portion can be secured to the inside of a pilot hole, tunnel or other opening formed in the bone.
There are different types of tissue anchors available. Some tissue anchors feature a bone anchor portion having a threaded or non-threaded body that is driven or tapped into a hole in the bone. Other types include “all-suture anchors”, which are made up of sutures that are anchored in the hole in the bone. Some all-suture anchors have sutures that are looped so that the sutures form a large knot after the sutures are advanced into a hole and pulled in tension. The cross-sectional footprint of the knot is larger than the cross-sectional area of the hole, allowing the knot to bear again the wall of the hole in a form fit. The pull-out strength of form fit knots in bony tunnels can vary. Inadequately secured knots pose a risk that the knot can be pulled out of the tunnel, causing detachment of the tissue anchor from the bone, and subsequent need for revision surgery and repair.